docs: def handle_quit(self, params):
          """
          Handle the client breaking off the connection with a QUIT command.
          """
          response = ':%s QUIT :%s' % (self.client_ident(), params.lstrip(':'))
          # Send quit message to all clients in all channels user is in, and
          # remove the user from the channels.
          for channel in self.channels.values():
              for client in channel.clients:
                  client.send_queue.append(response)
              channel.clients.remove(self)